A combined analysis of transcriptome and proteome reveals the regulation mechanism of alginate oligosaccharides on alleviating energy deficit in postharvest strawberry

Strawberry exhibits a very short shelf life due to its rapid softening and decay, resulting in postharvest loss. Our previous study showed that AOS, an eco-friendly nontoxic natural product, plays a role in preserving the freshness of strawberries by regulating ABA content and its signaling pathway. Considering the critical role that energy deficit plays in the senescence process of fruits, coupled with the potential influence of plant hormones on energy metabolism. In this study, the molecular mechanism of strawberry postharvest senescence in response to AOS treatment was further explored from the perspective of energy metabolism regulation. This was achieved through a two-layered approach, integrating the direct determination of energy-related substances with a comprehensive joint analysis of transcriptome and proteome data. AOS treatment significantly delayed the loss of ATP, ADP, and AMP contents compared to control fruit, implying that maintaining cell energy is a crucial factor in AOS postponing senescence in strawberry. Subsequently, the mechanisms were further revealed by transcriptome and proteome analysis. Overall, 255 DEGs were screened from the AOS group, mainly related to carbohydrate and energy metabolism, defense, plant hormone, and secondary metabolism. Additionally, A total of 227 proteins were identified that were differentially expressed in the AOS group, and the majority were related to carbohydrate and energy metabolism (85 proteins). Two omics data implied that AOS could effectively regulate the energy metabolism system to maintain the cellular energy level of harvested strawberry during storage, ultimately leading to longer shelf life. Therefore, our findings provide comprehensive information regarding the molecular mechanism underlying the postharvest storage of strawberry treated with AOS. From our results, it can be concluded that AOS postharvest treatment is very useful for keeping fruit quality and extending shelf life by maintaining a higher energy level.